Wait a minute, there are some serious mind boggglers here. I'm not a whm, but I AM a PLD.
1) Flashing an HNM should not be done by a whm, you will have a hasted PLD or 2 Tank hasted and they should have no troubles flashing. I you are in fact flashing, you're wasting mp.
Careful about flashing before your PLDs. Pretty sure it doesn't make a difference as far as enmity generation for the mob...but it generates enmity from the PLD to you <_<
Thats about the most retarded thing i've ever heard, flashing does not transfer hate from one to another. regardless of whether flash takes effect or not the enmity is still generated.
3)Devotion vs chivalry/convert: This is where good communication skills come into play. As a tank, when i know i am burning up MP and i am running low, i will ask or tell the whm in my pt when it would be a good time to use devotion, or tell them not to. Communicate.
Basically my use of Flash is dictated by how much trouble the tank is having. If they are /NIN and having trouble keeping shadows up, or some other sub and getting the poo beat out of them, then I'll Flash as often as I can without stepping on their Flashes. This helps them keep their enmity high by helping them to avoid damage, and also reduces healing costs.
On regular mobs that may work for you, but on HNM, that is NOT a ver smart way to play things. If i am getting the sh*t kicked out of me, then that means i am losing massive hate, if you are flashing, youre generating spikes of volatile enmity, and eventually, that HNM is going to come looking for that juicy ball of mp that used to be the whm curing me.
Besides, a WHM's flash is 10 times more likely to stick longer than a PLD's.
Paladin: Divine magic B+ 256 skill @ 75
White mage: Divine magic A- 269 skill @ 75
10 Times? not really.
Sir CorLeonisX: "Nah, SE will just declare it an exploit to fight him with jobs over 75 since it's not the "proper" way to kill it, and just ban us all instead."
Deadonarrival: "Dart as usual, your post is made of FAIL."